This invention relates to apparatus and methods for detecting very small anomalous masses, in particular tumors, in the human breast. In particular, this invention relates to detection heads for physically detecting breast anomalies and generating an electrical signal corresponding to changes in breast characteristics due to such anomalies.
Recent findings indicate that one of eight women will develop breast cancer, the second leading cause of cancer death in women. Unopposed estrogen activity is an important pathogenic factor, with other risk factors including nulliparity, early menarche, late menopause, a family history of breast cancer, middle age and prior breast cancer.
The earliest indication of breast cancer generally is the occurrence of a painless lump, sometimes associated with nipple discharge and skin retraction. Later symptoms are generally due to metastases to bone, brain, lungs and liver. Early diagnosis may be possible through monthly self-examinations. Mammography has proven beneficial in early detection.
When a very small lump,  less than 2 cm, is detected, a biopsy is generally performed, followed by treatment when the lump is found to be malignant. This can range from a lumpectomy with possible radiation treatment of axillary nodes to a modified radical mastectomy with axillary node dissection. With early treatment, the five-year survival rate is about 85%. Without early detection, if distant metastasis occur, the survival rate may drop to 10% or less.
Early detection of lumps is thus essential. Monthly self-examinations are very desirable, followed by examination by a physician if any suspicious areas are detected. It is, however, difficult for an unskilled person to detect very small lumps or to do a thorough examination.
Periodic palpation of the breasts by a physician and mammography will often detect very small tumors. These examinations should be reasonably frequent, particularly in older women, in order to detect tumors before they can metastasize. However the cost of frequent examinations, plus the accumulated radiation exposure from frequent mammograms tend to limit frequency. In addition, mammography may miss very small tumors, especially in the dense breasts of younger women. Further, pregnant women should avoid exposure to radiation.
Palpation of breasts will not detect very small changes and anomalies of the breast until the changes are so large or hard compared to the normal breast tissue that the difference can be detected by a touch of a finger. Generally, palpation is only capable of detecting changes where the anomalous tissue is relatively hard, has a diameter of at least about one centimeter and is close to the surface of the skin. Deeper anomalies, particular in large breasts, are difficult to detect by palpation. Since the characteristics of anomalies are not quantifiable, detecting changes in anomalies from one examination to another is difficult.
Thus, there is a continuing need for improved methods and apparatus for very early detection of very small breast anomalies that could be malignant, while avoiding radiation exposure.
The above-noted problems, and others, are overcome in accordance with this invention by an anomalies detection apparatus for thoroughly palpating entire breasts in a continuous, automatic scanning manner, to detect changes in breast tissue physical characteristics. In particular density is measured across the entire breast and, where anomalies are detected, mobility and size of the anomaly are measured.
The overall system of this detection apparatus includes a bed upon which the patient lies face up and which includes means for precisely positioning the patient in the same position for each of a series of periodic examinations. The detection head is mounted on a carriage for movement in three dimensions adjacent to a patient on the bed. A locator head associated with the detection head controls the bed positioning means to position the breasts in precisely the same position as for prior examinations. A palpation means on the detection head includes at least one finger-like palpation end movable toward and away from the breast surface to palpate the breast in the same general manner as a physician. The palpation device is preferably mounted so as to be movable across the entire breast surface sequentially while maintaining the finger generally perpendicular to the breast surface.
Information sensed by the palpation device is collected, stored and displayed in a conventional manner, such as is done with information from other systems such as computerized tomography and magnetic resonance imaging. The display will reveal, and show details of, any anomalies detected, so that further testing, such as through a biopsy, can be done.